Transformer



Apr; A17, 19'23.

S. HORELICK TRANSPORMER Filed July 21 1921 2 Sheets-Sheet l fw @Hoz/HWS Il." f.

Apr. 17, 1923. A 1,452,158

S. HORELICK TRANSFORMER Filed July 2l 1921 2 Sheets-Sheet Snom/woz Patented Apr. 17, 1923.

SAMUEL HORELICK, F PITTSBURGH,

PENNSYLVANIA, ASSIGNOB TO PITTSBURGH TRANBFORHER COMPANY, A. CORPORATION 0F PENNSYLVANIA.

TRANSFOBHER.

Application ma -nay 2i,

To all whom it may concern Be it known that I, SAMUEL Hoaaucx, a citi/.en of the United States, residing at Pittsburgh, in the county of Allegheny and 6 State of Pennsylvania, have invented cer-l tain new and useful Improvements in Transformers, of which the' following is-a specification.

This invention relates to electric trans- 10 farmers and particularly to `the construction of the coils and their relation to the core.

In general, the object of'lny invention is to provide an improved construction of dransformer which will be adapted to withstand high voltages without breakdown or loss in insulating properties with continued use, reduce leakage of current or flashing over between primary and secondary windings, or to the core, to a minimum, and be wel] ventilated and cooled with continuous operation at full capacity.

My invention'will he understood from the following description and accompanying drawings, in which Fig. 1 is a horizontal section of a core and coils of a transformer embodying my invention, Fig. 2 is a front view of the same, Fig. 3 is an enlarged vertical section on the line 3-3 of Fig. 1, with the lower part of the coils broken away, Fig.

4 is an enlar d perspective view of a top portion of tie insulating and vcntilating means between the windings; and Fig. 5 is an enlarged central vertical cross section through the core and coils in a plane parallel with the lamin.

Referring to Figs. 1 and 2, the laminated core 1 has a vertical central leg 1 and ontside legs l and upper and lower connecting portions l, formingr a core of the double magnetic circuit type. The coil is elliptically shaped and surrounds the middle leg 1, the latter preferably being so shaped as to conform in general outline to the interior surface of the coil 2. as shown in Fig-1. The transformer is of the type adapted to he immersed in oil in a tank, and the coil is provided with vertical passages bctwecn its parts so as to facilitate cooling of the coils and core by continuons circulation ofthe oil upwardly through the passages and downwardly at the outside of the transformer and adjacent to the interior walls of the enclosing tank.

Referring to Fig. 3. and beginninar nt the left-hand portion of the ligure. there is 4hating and cooling me 4enveloping' elliptical 19,21. Serial lo. 486,336.

shown a protective and insulating sheet of insulating material 3*,l such as insulating fiber hoard or press board, extending around the central leg of the core and forming an elliptical inner cylinder. Adjacent thereto is a. series of insulatin strips 4| extendin vvertically the height oiI the coil and sp from each other so as to provide a series of spaces for the upward assage of the circudium. Around these spaced strips is a winding 5* forming a portion of the low tension winding. The sconductors of thiswinding are square or rectangular cross section and each turn is suitably insulated from the adjacent turn by an insulating coating, or by being wound bv a cord of rope so that a large portion of the conductor is directly exposed to the cooling medium. Each turn may. be made of a single conductor or several bound and wound together. Outside the winding is another series of vertical insulating strips 4* spaced from each other, similar to the strips 4*. Outside these strips is another shaped cylinder 31, simand this is followed in turn by a serlesrof s paced insulating strips 41, 4*, 4" and 4, having interposed between them the insulating sheets 3', 3, and 3.

Around the Strips 4 is Wound a section 6 of the high tension winding of the coil. the turns of which are of course insulated from each other and may beformed of a single conductor or grouped conductors tn suit the particular requirements. Outside this section of the high tension winding is another enveloping sheet 3', then another series of insulating strips 4, and then another section 6 of the high tension winding. Outside this scction is an enveloping sheet 3' and then aseries of spaced strips 4, 4", 4, 4" and 4* with intervening sheets 3, 3, 3 and 3*. Around the strips 4 is another section 5 of the low tension winding, outside of which are spaced insulating strips 4 and au enveloping sheet 3. At the upper ends of the sections of the low tension windings, and between the upper cnds of the insulating strips 4 and 4* and between strips 4k and 4, are located'solid insulating packing strips, or strips of insulating press-hoard 7, 7". These strips extend continuously around at the upper end of the coil and protect and insulate the u per ends of the low tension windings. T 1-` upper ends of the high tension sections of the ilar to the sheet 3k preferably of lll) sages 8, 8', and likewise between the str ips 7', 7' and 7i, are similar passages 8.'I and 8 As regards the vertically extending spaeing strips 4to 4', it will be seen that'the scries of these strips between the high tension windings and the low tension windings do not all extend to the end of the coilstructure, and leave a space beyond their ends,

so as to form a long creepage or dischargeA path between the ends` of thehigh tension Awindings and the low tension windings. But

instead 'of all of the vertical strips between twoinsulating sheets being all shortened at one end, or extending completely to thc end of the coil structure, they are alternately arranged short and long.l This will be better understood from Fig. 4, which shows the upr end ortions of the sheets 3", 3", and 3' avin t e intervening strips 4", 4' and 4J, It wil be seen that every other strip 41 for example, extends to the top of the coil structure and the ends of the intervening strips are considerably below the top of the coil structure. Similarly the otherstrips are thus arranged so that the leakage path in any direction between the high tension and low tension windings is greatly increased over what it would be if all of the vertical insulating strips extended to the end of the coil structure. Moreover the alternateurrangement of any one set of strips, being arranged so .that the oppose the reversely arranged strips in t e next group` result in the insulating sheets being held firmly in sition and revent their curling or bending over int e continuedl use of the transformer and thus the cooling and veutilating passages are maintained open and clear at all times, while at the same time obtaining a much greater protection from leakage or discharge between the ends of the high tension and low tensionl windings.

It will be understood of course that the lower end of the coil structure is similarly constructed. The vertical insulating strips may be all made of the same length if desired, and displaced'as above described, so that a strip which extends the full distance to the top of the eoi'l structure will be inwardly displaced at the lower end and vice versa. The core structure is built up by first placing the sheet 3" on a mandril and then sur-ccssively applying the strips, windings, insulat ing sheets and packing strips until the whole Ascri struhre is finally built up as above dei The complete coil is then heated arid may be placed in a vacuum thoroughly drying the unlt throughout all its parts and is then Atreated with liquid varnish or other suitable material while still subjected to the vacuum and the structure thus becomes thoroughly impregnated with the insulating liquid, pressure being added. to increase the penetration. The coil structure is then drained and heated in the presence of air and thoroughly dried until the liquid insulating material is hardened, giving a final structure whiirh is thoroughly bound together, strong and durable and highly insu ated throughout all its parts. Moreover, all the surfaces are coated with the hardened` insulating liquid iving very smooth surfaces and forming filets in all the corners.\ This results not only in giving smooth surfaces for the easy and free passage of the oil through all the ven-Y tilating surfaces and permanence of structure, but also greatly decreases themleaka e or tendency to discharge between the eh s of the windings. Also when the transformer is immersed `in'oil in itsicontaining tank, it will be sven that there are located at the ends of the high tension windings between the series of packing strips 7" to 7*' the'oil pockets 8 to 8c.

It is apparent that by the means of my invention t ere is not only provided a long crcepage distance between the ends of the high tension and low tension windings, but also a number of solid insulating sections and oil filled spaces in successive sequence therewith.

The above description and drawings illustrate one embodiment of my invention, but the stmt-ture may be varied without departing from the scdpe thereof; also the wind ings may be grouped differently or differcntly` located with reference to each other and the number and relationship of the insulating sheets and spacing strips may be varied and differently proportioned to suit thc requirements of any particular case.

1. A transformer coil com rising windings, circumf'i-.rcntially exten ing sheets ot insulating material between portions of said windings, and axially extending insulatin strips spaced from each other ybetween said sheets and windings. certain of said strips extending nearer the end of the coil structure than other intermediate stri 2. A transformer coil com rlsin windings, circumferentially exten in s eets of insulating material between portions of-said windings, and axiallyV extending insulating strips spaced from each other between said sheets and windings, certain of said strips extending nearer the end of the coil struc ture than other'intermediate strips es` lon its

garda the path between -portions of the windingsf Y 3. A transformer coil com risin windin circumferentially exten ing sheets of insu atingmaterial between portions of said windings, andaxially extending insulatin strips spaced from each other between sai sheetsand windn certain of said strips extending nearer t e end of the coil 'structure than other intermediate strips as regards the circumferential direction between windings.

4. A transformer coil com risin windings circumferentially exten ing s eets of insulating material between portions of said windings, and axially extending insulatin strips spaced from each other between sai sheets and windings, certainof said strips extending nearer the end of the coil struc ture than other intermediate strips as regards the path between portions of the windings and also as regards the circumferential direction between windings.

5. A transformer coil comprising windings` axially extendin insulating strips between portions of sai windings, circumfrentially extending strips spaced from each other and located at the end of a portion of siiiil windings and having spaces between said circuniferentially extending strips communicating with spaces between the axially extending strips.

6. A transformer coil comprising windings, axialljl extendin insulating strips between portions of sai windings, circumferentially extending strips spaced from each other and located at the end of a portion of said windings and having spaces between.

insulating strips spaced from eac other an between said sheets and windings, and circumferentially extending insulatin strips spaced from each other at the end o at least a portion of said windings.

8. A transformer coil comprising windings, insulating sheets between portions of said windin s, axially extending insulating stri s space from `each other and between sai portions of said windings and said sheets, and circumferentially extending iii sulatin Strips spaced from each other at the en of at -least a portion of said windings, certain bf said axially extending strips extending to the end of the structure and intervening strips terminating at agdistance within the end of the structure.

SAMUEL HORELICK.

tween rtions of said windings, axiall extendin 

